GitLab

MVP with the same functionality as the current TabswitcherModeTTPhone Toolbar,
except for the animations.

Screen videos here:
https://drive.google.com/drive/folders/1bqxiTsr5SSX2p73eZrLao7GRA5ZwIkLw?usp=sharing

In follow up CLs:
Add animations.
Dynamically remove Google logo depending on screen width.
Dynamically change toolbar with OverviewModeState.
Add identity disc.

Bug: 1025296
Change-Id: I6b48b7854088469638a2a4cb22829f24c1e98fdc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1975051Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Reviewed-by: Patrick Noland <pnoland@chromium.org>
Commit-Queue: Mia Glaese <glamia@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728576}